The Neurology of Memory & Anterograde and Retrograde Amnesia

How is memory encoded and what methods can lead to greater recall? There have been many different models suggested for human memory and many different attempts at defining a specific method of encoding that will lead to greater recall. In this experiment subjects are asked to do a semantic task on a word related to them and an orthographic task in which they analyze the letter in the word. The results of the experiment indicate that the words which where encoded semantically and are related to the self have greater recall.

* Consolidation- hypothetical process involving gradual conversion of information into memory codes stored in long term memory.

The part of the brain that is in charge of memory is called the hippocampus, which is part of the cerebral cortex. The cerebral cortex is in charge of thinking, problem solving, and many different kinds of language skills. People that have a problem with their hippocampus can have trouble remembering new details they have taken in. There are also many different parts of the hippocampus that apply directly to the memory. These parts include short-term memory, long-term memory, sensory memory, and the constructive processes. Short-term memory is the information that stays in your brain only when you are thinking about it, about 20 to 30 seconds. After this, it is most likely forgotten. Long-term memory is when your hippocampus keeps track of facts you learn, ideas you have, and experiences. Even when people stop thinking about these things, the memory can last a lifetime. Another part of the hippocampus, sensory memory, remembers information only for one or two seconds. The brain creates a mental image that disappears when you stop directly thinking about a particular thing. The last part of the hippocampus is the constructive processes. Constructive processes are memories that your brain makes up in order to make sense of a detail in which you only remember some of the details. The few details that the brain remembers are combined with other small details that your brain adds in order for it to

Among these different processes are encoding, storage, consolidation, and retrieval. This study hypothesized that the hippocampus plays a different role in each of these. The method of this study is especially unique because it used temporary chemical inactivation of the hippocampus, which had not been done before. This temporary inactivation is unique because it lets the researchers selectively assess the role of the hippocampus during each of the processes discussed above. To test encoding, the inactivation occurred during learning of a maze task; to test retrieval, inactivation occurred during a retention task. Results indicate the temporary inactivation of the hippocampus impairs both encoding and retrieval. To test long-term consolidation, rats were trained and then separate groups received hippocampal treatment for different amounts of time between one and five days. Results showed that temporary inactivation during this time period disrupts memory for the already learned task. This study partially supports the result of the study by Eldridge et al. (2000) in that they both show the hippocampus is necessary for memory retrieval. However, it does not address the retrieval of different types of memory. This study also supports the idea from Wang et al. (2012) that the hippocampus may be involved in consolidation and storage of new memories but not necessarily of older

Anterograde Amnesia is the inability to store new information after the brain damage has occurred. (Luke Mastin 2010). Anterograde Amnesia is very rare, in fact there have a few cases where the amnesia was "pure". The symptoms and hardship of the person depend on the cause for the memory loss. Some symptoms of Anterograde Amnesia are partial memory loss, having a hard time recognizing relatives or family, feeling of confusion, difficulty taking in new information, inability to remember familiar places, and difficulty in learning and remembering new things.(PHC Editorial Team 2013) Characteristics of Anterograde Amnesia are abnormally small hippocampi bilaterally and elevated hippocampal water.(Mayo Clinic 2014) There are many ways to recognize

There are two main dimensions of amnesias. The first cause is physical or psychological; the second proceeds or follows a traumatic event. Most amnesia is a result either from organic or neurological causes (damage to the brain through physical injury, neurological disease or the use of certain drugs), The seriousness of the amnesia depends on the areas in which the brain is damaged. The second dimension is the dichotomy between forgetting the past versus an inability to form new memories. Terry, W. Scott. Learning and memory: basic principles, processes, and procedures. Boston, MA: Pearson, 2009. Print. Retrograde amnesia is not being able to remember events before the disorder. The amount of time that can't remember depends on the severity. Anterograde amnesia is the inability to form new memories, it is usually caused by severe brain trauma.

It is apparent that patient H.M.’s memory has not been affected by any general intellectual loss. H.M has severe anterograde amnesia, but surprisingly has spared implicit memory. Implicit memory is a type of memory in which past experiences aid the presentation of a task without mindful awareness of the experiences. There have been many tests conducted on the patient to test this spared memory.

Additionally, to further support these theories, researchers tend to conduct studies on the famous patient case, HM, to propose the consolidation deficit theory, in which those with amnesia cannot turn short-term memories into long-term memories (Dewar et al., 2010). However, researchers Dewar, Della Sala, Beschin, and Cowan (2010), mentioned that HM’s case does not fully explain why a patient with anterograde amnesia has the ability to get better at cognitive tasks despite being unable to recall having performed those tasks at a previous time. On the same hand, Duff, Wszalek, Tranel, and Cohen (2008) mentioned that most individuals with anterograde amnesia experience heightened intelligence, attention, skill, and reasoning levels (procedural memory).

The brain and the distinct parts have countless duties but one of the utmost vital ones is assembly and retain new memory. In the Brain… it says, “Structures within the temporal lobe, a region of the brain near your ears, are responsible for different types of learning.” Page 5. The temporal lobe aids learning and saves the information that can be used later. Learning is key to help humans and animals to survive and thrive. Learning allows living beings to be able to do old tasks and new tasks. “… The hippocampus gathers all of the sensory aspects of the event and conducts soon initial processing of these sensory elements into a neurological format that elements that are not completely understood.” Said in the Brian, page 6. The hippocampus keeps a

Hippocampus is a small, curved region, which exists in both hemispheres of the brain and plays a vital role in emotions, learning and acquisition of new information. It also contributes majorly to long term memory, which is permanent information stored in the brain. Although long term memory is the last information that can be forgotten, its impairment has become very common nowadays. The dysfunction is exemplified by many neurological disorders such as amnesia. There are two types of amnesia, anterograde and retrograde. Anterograde amnesia is inability in forming new information, while retrograde refers to the loss of the past memory. As suggested by Cipolotti and Bird (2006), hippocampus’s lesions are

The functional domains that lie within the province of retrograde memory need to be clearly specified. During a person’s lifetime we build up an enormous store of knowledge, experience, and skills. The article states that “Until recent years, it has most commonly been used to refer to the loss of memory for events that had preceded

After a new memory is learnt, it enters the process of encoding during which the memory is labile and capable of disruption until it becomes stabilised over a period of time (Nader & Einarsson, 2010; Nader et al, 2000). This process is called consolidation and originally consisted of the theory that once stabilised in the brain, it remains fixed (Suzuki et al, 2004). This theory has been rebutted by the acceptance of reconsolidation, a theory that imposes the ideology that when memories are retrieved, through similar experiences (Lee, 2009), they become labile until,

When I heard the bells ringing it was stored in my short term memory, and it was later stored in long-term memory. Today if I hear alarm clocks it may trigger the same response as the school bell due to overlap within consolidation. Consolidation is when an event is encoded and stored into a memory (Mastin, 2010). These emotional memories are stored so vividly within memory

A human’s memory system is just one of many amazing things that demonstrate the brain’s complexity. Without memory we would have no recollection of anything, ever. Within our memory system there are three main measures that assess how much information is retained, these are known as recall, recognition and relearning. These are all measures of retention, that influence how much information is encoded, stored and retrieved within one’s memory system. Each measure of retention has a different level of sensitivity. The more sensitive a measure of retention, the easier it is to retain information.

In both study conditions, successful encoding was associated with significant activations in the bilateral hippocampus in addition to the dorsolateral and ventrolateral prefrontal cortex. These activations were more pronounced during deep processing verses shallow processing. The results of this study is consistent with recent research by showing that successful encoding for later episodic memory is associated with increased neural connectivity, which is the precondition during successful retrieval. Memory traces reside in neocortical areas, coordinated by the hippocampus. This hippo-campal-cortical connectivity increases during successful encoding and we can see that this was more pronounced during successful deep level encoding, which means deep level encoding leaves behind more distinctive and retrievable memory traces.